The invention is in the field of tape feeders, particularly feeders for stepwise indexing of tapes having pockets containing surface mountable electrical components.
The feeder advances the tape stepwise to sequentially present each pocket to a pick-up station where the component is removed from the pocket for subsequent handling such as transfer to a conveyor or direct placement onto a circuit board. Typically, a top cover of the tape is peeled or split to provide access to the pocket, and loss of components from open pockets has been a problem with prior art feeders.
Several types of supply tapes are presently used. One type has a plastic substrate embossed to define component holding pockets which are enclosed by a thin plastic top cover. Another type has a cardboard substrate with holes therethrough to define the component pockets and top and bottom covers for the holes. With the cardboard substrate type, the covers are a thin flexible plastic material such that the bottom cover often deforms, if not additionally supported, during removal of the component from the pocket. During such cover deformation, the component sometimes gets "hung-up" on the substrate material and pick-up of the component fails.
Accordingly, it is an object of this invention to provide a method and apparatus for preventing loss of components from opened pockets prior to their removal by the vacuum tube or spindle of a pick and place head or the like.
Other objects of the invention will become apparent from the disclosure that follows.
In a preferred embodiment, the supply tape is stepped to present each pocket at a pick-up area at which the component is removed from the opened pocket. Each pocket is opened in turn during the last step of indexing that positions it at the pick-up area, and a shutter is moved over the pick-up area prior to tape movement so that the pocket becomes covered by a shutter during the tape movement when the top cover is peeled from the substrate. After each indexing step, the shutter is moved to uncover the pick-up area, and provide access to the component in the opened pocket.